It is a highly debated topic as some believe that short ranged weather alteration can be possible to an extent but not enough to make anything drastic occur such as snow in the middle of a heat wave.

The link above leads to a website that claims that magick can set anything on fire and that you have to gain magickal abilities rather than them occuring naturally, the page also leads you to an advertisement, these kind of pages are to be taken with a pinch of salt and nothing more.

Does it ever rain when you don't cast a spell? Does it ever snow when you don't cast a spell?
If you cast a rain spell, when does it rain? In the next hour? The next day? The next week? The next month?
If you can make it rain,believe me, Saudi Arabia will pay you in millions!